1. Field of the Invention
This invention relates to a phase shifter, which is capable of changing a signal phase, and an antenna device equipped with that phase shifter.
2. Description of the Related Art
Conventionally, a phase shifter that is provided in a triplate line including a pair of outer conductors and an inner conductor arranged therebetween and is capable of changing a phase of a signal propagating in the inner conductor has been known (Refer to e.g. JP-A-11-340705).
The phase shifter disclosed in JP-A-11-340705 includes a plate-shaped dielectric coupled to a driving rod to be moved forward or backward. The forward or backward movement of the driving rod results in the dielectric moving in a direction of crossing the inner conductor, and varying the proportion that the dielectric occupies in the spaces between the inner conductor and the pair of outer conductors respectively. Thus, a variation in effective permittivity of the triplate line occurs, resulting in a variation in electrical line length and therefore a variation in the phase of the signal propagating in the inner conductor (e.g., as shown in FIG. 4 of JP-A-11-340705).
Refer to e.g. JP-A-11-340705 (paragraph, FIG. 4).